1. Field of the Invention
The present invention relates generally to the field of continuous haulage of coal or ores in underground or surface mines, and more specifically, to a flexible mobile bridge conveyor having a unique linkage and suspension to interconnect articulated, modular, self propelled bridged conveyor carriages.
2. Description of the Related Art
In conventional underground mining, a series of roadways (known as "rooms") and pillars are formed, while the coal or ore is excavated by a continuous mining machine. The roadways undulate, are generally very rough, and extend in several directions. In such mines, visibility is severely limited around the labyrinth of roadways and pillars due to poor lighting conditions and numerous obstructions.
Recently, several systems have been designed and built to convey the output of the continuous mining machine in a steady and uninterrupted flow to a remote transfer/loading point, in order to enhance the overall productivity of the operation. These systems have employed "bridge" conveyors, which consist of a series of interconnected vehicles that overlap each other to form "bridges" from one end of the conveying train of vehicles to the other.
Each of the individual bridges or carriages has a conventional belt or chain-and-flight type conveyor that moves the material loaded onto the bridge conveyor by a continuous mining machine from one end of the bridging vehicle to its other end. The material is transferred to each subsequent bridge, thus being delivered to the end of the series of interconnected carriages or vehicles. Each vehicle runs on a transversely aligned axle or axle with a set of wheels mounted on the ends of the axle or crawler-type carrying means, with the wheels or crawlers being driven by conventional means, such as an electric motor.
An important aspect of a continuous conveying system is its ability to negotiate corners (around the many pillars) and to traverse over the severely undulating and rough roadways. Breakdowns of such a system operating under the harsh environment of a mine are greatly reduced if the overall design is simple with a minimum of control mechanisms. Thus, a train of bridge conveyors needs to be simple, flexible, and operable with a minimum of manpower.
Commercially available bridge conveyors do not satisfy the above-noted needs. One commercially available system is manufactured by Kloeckner-Becorit. It features a continuous haulage system of bridge conveyors which cannot be moved while conveying the material because the whole train of vehicles have to be lowered for tramming and then raised for conveying. Such a system is briefly described in Coal, June 1989 edition.
Another commercially available conveyor is made by Long-Airdox. Also described in Coal magazine, this system requires several operators, one for each set of two bridges. If several operators are not used, these trains of bridge conveyor carriages are unable to follow or track behind the preceding train or vehicle, thereby resulting in major tramming problems. Unfortunately, the use of many operators for such conveyor train systems results in undesirably high operating costs.
Known means of coupling multiple vehicles together to form trains of bridging conveyors include variations of a standard ball and socket trailer hitch arranged and supported from structure attached generally to the end elements of each vehicle. This is considered to be unsuitable for the purposes of a bridging conveyor system in that the pivoting ball and socket joint with supporting structure generally interferes with the preferred material flow path between the conveyor elements of individual vehicles of the train.